A pixel unit of a display device typically comprises three sub-pixels which emit light independently and, for example, are a red (R) sub-pixel, a green (G) sub-pixel, and a blue (B) sub-pixel, respectively. By controlling the components of three colors (RGB) corresponding to the three sub-pixels in the pixel unit, respectively, the color and the brightness displayed by this pixel unit may be controlled. This pixel structure in which RGB sub-pixels are alternately arranged is referred to as an RGB arrangement. In addition, the pixel arrangement structure further includes a pentile arrangement in which the number of red and blue sub-pixels is reduced by a half.
At present, there are two relatively developed production approaches for sub-pixels of display devices such as organic light-emitting display devices (OLEDs) and quantum dot display device (QLEDs). One employs a manner of evaporation, and the other one employs a manner of inkjet printing. With respect to the two existing pixel structures described above, they are limited by conditions of facilities despite of production approaches. With respect to an evaporation method, the size of each sub-pixel is limited by the size of the opening of a mask plate. With respect to an inkjet printing method, the size of each sub-pixel is limited by the size of the orifice size of a print head.